1. Field of the Invention
The invention relates primarily to the field of computer software, and in particular to a method and apparatus for formula evaluation in spreadsheets on small devices, such as Personal Digital Assistants (henceforth referred to as PDAs).
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2. Background Art
PDAs are small hand-held computers that perform a plurality of tasks. Like conventional computers, PDAs have memory. Memory is necessary for the execution of a task. Some of these tasks, like calendar and appointment schedules, are simple and require very little memory. Others, like spreadsheet applications, are complex and require a lot of memory. When users want to use memory intensive applications on a PDA, such as a spreadsheet program, they encounter problems because PDAs by their nature have a limited amount of memory.
Computer users sometimes wish to use the same applications and data sets on their PDA that they use on their general purpose computer (or desktop). However, the format of the files used on similar programs on both the PDA and desktop is very different. This is due to the fact that the operating system that controls a PDA is different from a desktop operating system. Because of the different operating systems, the same kind of programs for both the PDA and desktop require different amounts of memory. PDA version programs may sometimes use more memory than is available on the PDA. In some cases, a user may need to quit programs and delete data from their PDA in order to make room for a data set, especially for large programs like a spreadsheet application. This limits the versatility of the PDA. Before further discussing the drawbacks associated with PDAs, a general description of PDAs is provided below.